The microstructure, phase structure, ferroelectric, and dielectric properties of (1 -x)Bi 0.5 Na 0.5 TiO 3 -xNaNbO 3 [(1 -x)BNTxNN] ceramics conventionally sintered in the temperature range of 1080°C-1120°C were investigated as a candidate for capacitor dielectrics with wide temperature stability. Perovskite phase with no secondary impurity was observed by XRD measurement. With increasing NN content, (1 -x)BNT-xNN was found to gradually transform from ferroelectric (x = 0-0.05) to relaxor (x = 0.10-0.20) and then to paraelectric state (x = 0.25-0.35) at room temperature, indicated by P-I-E loops analysis, associated with greatly enhanced dielectric temperature stability. For the samples with x = 0.25-0.35, the temperature coefficient of capacitance (TCC) was found <11% in an ultra-wide temperature range of -60°C-400°C with moderate dielectric constant and low dielectric loss, promising for temperature stable capacitor applications.

Relaxor-ferroelectric ceramics capacitors have been in the front line of investigations aimed at optimizing energy density due to their high P_max, suppressed P_r, and high BDS levels, attributed to their highly dynamic polar nano-regions.

30% carbon fiber reinforced polyetheretherketone (CFR-PEEK) has in recent times, become significant in the orthopedic industry because its elastic modulus can be engineered to match that of the human bone. But it is bioinert and does not integrate well with the immediate bone tissue environment. In this study, a combined surface modification technique involving ambient temperature sulfonation and surface coating of (hydroxyapatite (HA), 5%reduced graphene oxide hydroxyapatite(5%RGO/HA) and 10%reduced graphene oxide hydroxyapatite(10%RGO/HA) composites) on 30% CFR-PEEK was achieved with an appropriate temperature treatment at 345 C in nitrogen. The coatings adhered unto the surface of S30%CFR-PEEK with an improved hydrophilicity and bioactivity. With the sample S30%CFR-PEEK+HA, having the highest enhanced hydrophilicity from 112.5 ± 2.5 to 20 ± 2 and bioactivity.An improvement in hydrophilicity and bioactivity depicts a change in surface chemistry which will have a positive impact in the interaction of the materials surface with immediate bone environment for a successful application in the orthopedic industry.

The current work presents the designed series of compositions within pseudocubic regions based on (1−x)La 0.03 Na 0.91 NbO 3 −xBi(Li 0.5 Nb 0.5 )O 3 ceramics abridged as (1−x)LNN−xBLN meant for energy storage applications. The addition of Bi(Li 0.5 Nb 0.5 )O 3 (BLN) considerably disrupted the ferroelectric order of the La 0.03 Na 0.91 NbO 3 (LNN) ceramics and favored the perfection of the energy storage density properties. Material properties like breakdown strength (BDS), charge−discharge efficiency (η), and dielectric loss of the system were enhanced via the incorporation of BLN into LNN. The external electric field supply into the system drastically enlarged the energy storage density, where the maximum recoverable energy density value of 2.02 J cm −3 at 300 kV cm −1 was achieved in 0.88LNN−0.12BLN ceramics. Besides this, the new system also demonstrates a strong ability to withstand stress (fatigue-free character) and sound temperature stability characteristics. The impressive storage density, temperature stability, cycle stability, and frequency stability credited to a steady relaxor pseudocubic phase covering a broad temperature range describes the newly designed system. The results demonstrate the potential for the (1−x)LNN−xBLN ceramics as the promising lead-free energy storage materials.

No abstract